Do not provide your Paysera login data to anyone as it is not safe. The programmer has to register in the Paysera system and create their own account.
Afterwards, go to your Paysera account, select Projects and Activities > My Projects and click on Project settings > Administration rights. Enter the programmer's “Unique number, or confirmed phone number, or confirmed email address“ and check the box next to the permission Change technical parameters of the project (the right for a programmer) and press the button Grant rights.
Programmers will be able to manage your project's technical parameters, but will not have access to your Paysera account.