You have two options:
1) Pass the parameter
sessid in your username.
The session ID value can be any random generated string. While using same string, you will be assigned with the same IP. For example:
customer-username-sessid-random1234. For every request in which you will use session ID of
random1234 your request will go through the same IP. However, the default session time is 10 minutes, which means that after 10 minutes from when you start using a specific session id, your session will expire and you will be assigned with a new IP.
2) Use sticky entry point.
Look at your dashboard section Entry Points and choose an entry point from Sticky Proxy Entry Points. Entry points are combined from entry node which refers to specific country and port which refers to session. It means that while you use same port all of your requests will go through the same IP, but as well as in the first option, default session time is 10 minutes. For example, if you need UK sticky proxy, as entry node you should choose
gb-pr.oxylabs.io and port from 20001 to 29999 (According to dashboard’s page Entry Points).