धोखाधड़ी की शिकायत दर्ज कीजिए ताकि कर्मचारी कार्ड ब्लॉक कर सके।

की is the genitive marker here, linking two nouns.
So धोखाधड़ी की शिकायत literally means a complaint of fraud or a fraud complaint.

• धोखाधड़ी = fraud
• शिकायत = complaint
• की = of

Hindi often connects one noun to another this way instead of simply putting two nouns together as English does.

दर्ज करना means to register, to file, or to record something officially.

In this sentence, शिकायत दर्ज कीजिए means please file/register the complaint.

This is a very common formal expression in Hindi:

• रिपोर्ट दर्ज करना = to file a report
• शिकायत दर्ज करना = to file a complaint

Because कीजिए is the polite command form of करना.

The full verb is दर्ज करना. When you turn that into a polite instruction, it becomes:

• दर्ज कीजिए = please register/file it

This pattern is very common with compound verbs made from a noun/adjective + करना:

• फोन कीजिए = please call
• शुरू कीजिए = please begin
• दर्ज कीजिए = please register/file

So कीजिए here is what makes the sentence a polite request or instruction.

Yes, कीजिए is polite and respectful.

Other possible forms include:

• दर्ज करें = please register/file (also polite, very common in formal instructions)
• दर्ज करिए = also polite, though कीजिए often sounds more standard with this kind of compound verb
• दर्ज करो = informal command
• दर्ज कर = very informal / blunt

So दर्ज कीजिए is a good choice for customer-service language, public instructions, or formal speech.

ताकि means so that or in order that.

It introduces a purpose clause.
So the sentence structure is:

• शिकायत दर्ज कीजिए = file the complaint
• ताकि कर्मचारी कार्ड ब्लॉक कर सके = so that the employee can block the card

In other words, the first action is done for the purpose of making the second action possible.

Because after ताकि, Hindi often uses a verb form that expresses purpose, possibility, or intended result.

Here:

• कर सके = can be able to do / may be able to do
• ब्लॉक कर सके = can block

This is more natural after ताकि than something like ब्लॉक करता है, which would describe a regular action rather than a purpose.

So:

• ताकि ... कर सके = so that ... can do

सके comes from the verb सकना, which means to be able to or can.

In ब्लॉक कर सके:

• कर = do
• सके = be able to

Together, ब्लॉक कर सके means be able to block / can block.

So the employee is not just doing the action; the complaint makes it possible for them to do it.

Good question. कार्ड को ब्लॉक कर सके is also possible.

In Hindi, को with a direct object is often omitted when the object is inanimate, general, or already clear from context. Since कार्ड is an inanimate object, leaving out को sounds normal.

So both are possible:

• कार्ड ब्लॉक कर सके
• कार्ड को ब्लॉक कर सके

The version without को is concise and very natural in practical instructions.

Yes, very normal. Modern Hindi very often uses English loanwords, especially for banking, technology, customer service, and administration.

So expressions like these are common:

• कार्ड ब्लॉक करना
• फॉर्म भरना
• ऑनलाइन आवेदन करना
• मैसेज भेजना

Here, ब्लॉक करना works like many Hindi-English compound verbs: an English word plus करना.

So this sentence sounds natural in real-world Hindi, especially in a banking or fraud-reporting context.

It depends on context, because Hindi does not use articles like a and the.

So कर्मचारी can mean:

• the employee
• an employee
• a staff member
• sometimes even staff, depending on context

In this sentence, it most naturally means something like the staff member / employee handling the complaint.

The sentence follows a very normal Hindi pattern:

• main instruction first: धोखाधड़ी की शिकायत दर्ज कीजिए
• purpose clause after that: ताकि कर्मचारी कार्ड ब्लॉक कर सके

Hindi often places the purpose clause after the main clause in sentences like this.

Also notice the verb-final tendency:

• कर्मचारी कार्ड ब्लॉक कर सके The main verbal idea comes at the end, which is typical in Hindi.

Yes, that is very close to the literal structure.

A more natural English translation would usually be:

• Please file a fraud complaint so that the employee can block the card.

But the more literal breakdown is helpful for learning:

• धोखाधड़ी की शिकायत = complaint of fraud
• दर्ज कीजिए = please register/file
• ताकि = so that
• कर्मचारी = employee/staff member
• कार्ड ब्लॉक कर सके = can block the card / may be able to block the card

So your literal understanding is on the right track.