Co se týče repatriace, potřebuji potvrzení o pojištění.

Yes — co se týče is a very common fixed expression meaning as for, regarding, when it comes to, or as far as ... is concerned.

So:

• Co se týče repatriace... = As for repatriation...
• Co se týče víza... = As for the visa...

It comes from the verb týkat se (to concern / to relate to), but learners usually memorize co se týče as one whole phrase.

The expression co se týče is followed by the genitive.

So grammatically, repatriace here is in the genitive singular.

A useful thing to know is that with this noun, the nominative singular and genitive singular look the same:

• nominative: repatriace
• genitive: repatriace

So even though the case has changed, the form has not visibly changed.

Compare with a noun where the change is easier to see:

• co se týče pasu = as for the passport
• pas → pasu clearly shows the genitive

Because Co se týče repatriace is an introductory phrase at the start of the sentence.

Czech often separates this kind of framing expression with a comma:

• Co se týče repatriace, potřebuji potvrzení o pojištění.

This is similar to English punctuation in sentences like:

• As for repatriation, I need proof of insurance.

Potřebuji means I need.

It is the 1st person singular present tense of potřebovat (to need):

• já potřebuji = I need
• ty potřebuješ = you need
• on/ona potřebuje = he/she needs

In everyday spoken Czech, you will also often hear potřebuju instead of potřebuji. Both mean the same thing:

• potřebuji = a bit more standard/written
• potřebuju = very common in speech

Here potvrzení means something like:

• confirmation
• certificate
• written proof

In this sentence, it most naturally refers to a document confirming that you have insurance.

The noun comes from the verb potvrdit (to confirm).

So:

• potvrzení o pojištění = confirmation/certificate/proof of insurance

The best English translation depends on context, but the Czech is perfectly natural.

Because in Czech, potvrzení o + locative is a very common pattern meaning confirmation/certificate concerning ... or proof of ....

So:

• potvrzení o pojištění = proof/certificate of insurance
• potvrzení o studiu = confirmation of student status / proof of study
• potvrzení o zaměstnání = confirmation of employment

Using o here is idiomatic.
Potvrzení pojištění would sound unnatural or incomplete in most contexts.

After o, the noun is in the locative.

So pojištění here is locative singular.

Again, the form happens to look the same as the dictionary form:

• nominative: pojištění
• locative: pojištění

That is why you do not see a visible ending change.

A clearer example would be:

• o smlouvě = about the contract
• o škole = about the school

There the locative ending is easier to notice.

Usually pojištění means insurance as a concept, coverage, or insured status.

So in this sentence:

• potvrzení o pojištění = a document proving that insurance exists

If you want to refer to the actual policy document, Czech may also use pojistka in everyday language.

A rough distinction is:

• pojištění = insurance / insurance coverage
• pojistka = insurance policy, policy document, sometimes just insurance in casual speech

So this sentence is talking about proof that you are insured, not naming the policy itself.

Yes, the word order is natural.

The sentence starts with the topic:

• Co se týče repatriace = as for repatriation

Then it gives the main message:

• potřebuji potvrzení o pojištění = I need proof of insurance

This is a very normal Czech structure: topic first, then the main statement.

Other wordings are possible, but they may sound less neutral or shift the emphasis. For example:

• Potřebuji potvrzení o pojištění, co se týče repatriace.
  This is much less natural.

So the original version is a good model to learn.

Co se týče is neutral to slightly formal. It is very common in writing and careful speech.

A common alternative is ohledně:

• Ohledně repatriace potřebuji potvrzení o pojištění.

That also means regarding repatriation.

Very roughly:

• co se týče = as for / when it comes to
• ohledně = regarding / concerning

Both are useful, but co se týče is especially good to learn as a standard phrase for introducing a topic.