पिन और पासवर्ड बदलिए ताकि बैंक खाता सुरक्षित रहे।

बदलिए is the polite imperative form of बदलना (to change). It is used when giving a respectful instruction, advice, or request to you in the आप form.

So this sentence is speaking politely, as in a notice, warning, or formal recommendation.

Compare:

• बदलिए — polite
• बदलो — informal, for tum
• बदल — very informal, for tu

Yes. बदलें can also be used as a polite imperative, and it is very common in written Hindi.

So both of these are natural:

• पिन और पासवर्ड बदलिए
• पिन और पासवर्ड बदलें

The version with बदलिए can sound a little more explicitly polite or instruction-like. In modern spelling, बदलिए is generally preferred over बदलिये, though you may still see both.

Because पिन और पासवर्ड are direct objects here, and in Hindi, direct objects do not always take को.

With inanimate things, को is often omitted, especially in general instructions like this:

• किताब पढ़िए
• दरवाज़ा बंद कीजिए
• पासवर्ड बदलिए

If you added को, it would sound less natural here. The zero-marked object is the normal choice.

ताकि means so that or in order that. It introduces a purpose clause.

So the structure is:

• main action: पिन और पासवर्ड बदलिए
• purpose/result wanted: ताकि बैंक खाता सुरक्षित रहे

This is a very common Hindi pattern:

• जल्दी निकलो ताकि समय पर पहुँचो
• अच्छी तरह पढ़ो ताकि परीक्षा पास हो

After ताकि, Hindi usually uses the subjunctive to express a desired result, purpose, or intended outcome.

So:

• रहे = may remain / stays / remain
• रहेगा = will remain (more like a future statement or prediction)
• रहता है = remains / stays habitually or a general fact

In this sentence, the speaker is not just describing the future. They are saying what should happen as a result of changing the PIN and password. That is why रहे fits best.

Because बैंक खाता is singular.

Here रहे is the third-person singular subjunctive form, used with खाता (account). If the noun were plural, you would use रहें:

• बैंक खाता सुरक्षित रहे — singular
• बैंक खाते सुरक्षित रहें — plural

So the form matches the singular noun खाता.

बैंक खाता is a compound noun meaning bank account.

If you said बैंक का खाता, it would more literally mean the bank’s account or an account belonging to the bank, which is a different idea.

This kind of compound is very common in Hindi:

• रेल स्टेशन
• बस स्टैंड
• मोबाइल नंबर
• बैंक खाता

So बैंक खाता is the normal way to say bank account.

Hindi often leaves out possessive words when the meaning is obvious from context.

Since the sentence is telling someone to change their PIN and password, it is already understood that the account is your bank account. So बैंक खाता is enough.

You could add a possessive for emphasis:

• ताकि आपका बैंक खाता सुरक्षित रहे
• ताकि अपना बैंक खाता सुरक्षित रख सकें

But in a short instruction, leaving it out sounds completely natural.

Yes. They are very common loanwords from English, written in Devanagari:

• पिन = PIN
• पासवर्ड = password
• बैंक = bank

Modern Hindi uses many English-origin words, especially in technology, banking, administration, and daily urban speech. A sentence like this sounds very natural to Hindi speakers.

It has more of a stay/remain secure feeling, because रहना means to remain / stay.

So सुरक्षित रहे suggests continuing security, not just a one-time state. In natural English, depending on context, it may be translated as:

• so that the bank account remains secure
• so that the bank account stays safe
• so that the bank account is secure

All of these capture the idea, but remain/stay secure is closest to the Hindi structure.

Yes. A very common alternative is to use ...रखने के लिए (in order to keep...):

• अपने बैंक खाते को सुरक्षित रखने के लिए पिन और पासवर्ड बदलें।

This means essentially the same thing. The difference is just in structure:

• ताकि...रहे = so that...remains
• ...रखने के लिए = to keep...

Both are natural, and learners should get used to both patterns.