Search function on Database

Hello community

I have a question.

We have a website where we display a list of customers coming from a database.

Because of we expect to have several customers, we would like to reduce this big range.

We would like to set up a pre-filter function for example “post code” or “location” -input to narrow down the search.

Can someone tell me please how this works?

Thank you in advance

Is there no one who can help?

Maybe there is a instruction somewhere available?
Every hint is welcome!