I wanted to modify or even create a new interface in User XP, but I am working with version 5.9.1 and I see that it is not available in the community version. What do you recommend me?
Hello, that option is only available with the Teamwork (paid) version of Bonita. See:
https://documentation.bonitasoft.com/5x/bos-59/web-applications/change-look-and-feel-web-forms