Custom Field Keyword or Tag with "add" function

I would like to give the user the opportunity to add keywords / tags to their profile. how can I implement this?

I don't want to use texarea. I would prefer a text field with e.g. + or add can be duplicated. So to speak, a text field group with an add option. Alternatively, a select list with the option to add values ​​would also be conceivable.

Is there a way to implement this in the standard? If not, I would be very grateful for a tip that would point me in the right direction...

Thanks in advance
marcus