Tôi hỏi về bảo mật tài khoản.

Hỏi means to ask.

When you add về, hỏi về means to ask about a topic.

So in this sentence:

• Tôi hỏi = I ask / I asked
• Tôi hỏi về bảo mật tài khoản = I ask / asked about account security

A useful comparison:

• Tôi hỏi anh ấy. = I ask him.
  (asking a person)
• Tôi hỏi về vấn đề này. = I ask about this issue.
  (asking about a topic)

So về works like about here.

Yes. Hỏi can be used in different patterns.

Common ones:

• hỏi + người = ask someone
  
  • Tôi hỏi nhân viên. = I ask the staff member.
• hỏi + người + câu hỏi / điều gì = ask someone something
  
  • Tôi hỏi cô ấy một câu. = I ask her a question.
• hỏi về + chủ đề = ask about a topic
  
  • Tôi hỏi về bảo mật tài khoản. = I ask about account security.

So về is not always required, but it is natural when the sentence focuses on the subject matter being asked about.

It can mean either I ask or I asked, depending on context.

Vietnamese verbs do not change form for tense the way English verbs do. The verb hỏi stays the same.

Time is often understood from context, or shown with time words such as:

• Hôm qua tôi hỏi về bảo mật tài khoản. = Yesterday I asked about account security.
• Bây giờ tôi hỏi về bảo mật tài khoản. = Now I’m asking about account security.
• Tôi sẽ hỏi về bảo mật tài khoản. = I will ask about account security.

So by itself, Tôi hỏi về bảo mật tài khoản is tense-neutral.

Vietnamese does not use articles like English does.

So:

• tài khoản can mean account, an account, or the account
• bảo mật tài khoản can mean account security or the security of the account, depending on context

Vietnamese usually relies on context instead of articles.

If a speaker wants to be more specific, they may add other words, for example:

• tài khoản này = this account
• tài khoản đó = that account
• một tài khoản = an account / one account

In Vietnamese, modifiers often come after or before in ways that do not match English exactly, and noun combinations are very common.

Here:

• bảo mật = security / protection / secure
• tài khoản = account
• bảo mật tài khoản = account security

This is a compact noun phrase, similar to English noun-noun combinations like account security, data protection, or password reset.

If you say tài khoản bảo mật, that would sound more like a secure account or security account, depending on context, so it is not the intended meaning here.

It can function in more than one way depending on context.

Common uses:

• as a verb: bảo mật thông tin = secure/protect information
• as an adjective-like word: hệ thống bảo mật = security system / secure system, depending on context
• as a noun: bảo mật tài khoản = account security

This flexibility is normal in Vietnamese. Many words can serve different roles without changing form.

Yes, in some contexts, but it changes the feel.

• Tôi hỏi về bảo mật tài khoản. explicitly says I.
• Hỏi về bảo mật tài khoản. without tôi sounds incomplete by itself in many situations, unless it is part of notes, headlines, short messages, or a larger conversation where the subject is already obvious.

Vietnamese often drops subjects when they are understood, but for a clear standalone learner sentence, Tôi is natural.

A rough English-friendly guide:

• Tôi ≈ toy
• hỏi ≈ something like hoy with a dipping/asking tone
• về ≈ vay with a falling tone
• bảo ≈ roughly bao with a dipping tone
• mật ≈ mut with a short, clipped ending
• tài ≈ tie
• khoản ≈ roughly khwan with a dipping tone

A few pronunciation notes:

• kh is like a breathy k sound, somewhat like the ch in German Bach for some speakers.
• hỏi, bảo, and khoản have tones, and tones matter a lot in Vietnamese.
• tài khoản is usually said smoothly as one phrase.

If your goal is communication, it is especially important to learn the tones on:

• hỏi
• bảo
• khoản

Yes, it is grammatical and understandable. It sounds like I asked about account security or I am asking about account security.

However, in real conversation, speakers might often say something a little fuller depending on the situation, for example:

• Tôi muốn hỏi về bảo mật tài khoản. = I would like to ask about account security.
• Tôi có câu hỏi về bảo mật tài khoản. = I have a question about account security.
• Tôi đang hỏi về bảo mật tài khoản. = I’m asking about account security.

So your sentence is correct, but in customer-service or formal situations, a longer version may sound more natural.

In customer service or support contexts:

• hỏi về + topic is used when you want to mention the subject you are inquiring about
  
  • Tôi hỏi về bảo mật tài khoản.
• hỏi by itself may focus more on the act of asking, or it may need an object/person
  
  • Tôi hỏi nhân viên hỗ trợ. = I asked the support staff member.
  • Tôi hỏi một câu. = I asked a question.

If you are saying what topic your question concerns, hỏi về is the most straightforward pattern.

Yes, but it sounds more formal and less compact.

Compare:

• bảo mật tài khoản = compact, natural, common
• sự bảo mật của tài khoản = the security of the account

The second version is more explicitly noun-based because of sự, which often turns an action or quality into a noun-like idea. But in everyday Vietnamese, the shorter version is usually preferred when the meaning is clear.

So:

• Tôi hỏi về bảo mật tài khoản. = more natural in many situations
• Tôi hỏi về sự bảo mật của tài khoản. = more formal, more analytical

Usually, tài khoản means account, especially in contexts like:

• bank account
• user account
• online account
• social media account

By itself, it does not have to mean an online account, but in a sentence with bảo mật, many people will naturally think of a digital or login-related account unless the context suggests otherwise.

Examples:

• tài khoản ngân hàng = bank account
• tài khoản email = email account
• tài khoản người dùng = user account

So in your sentence, tài khoản most likely refers to some kind of user or online account.