I'm doing an investigation and I have a problem that I can be solve. The date of birth can not be higher than the date of the survey

Welcome to the ODK forum, @leader76 ! We're glad you're here. When you get a chance, please introduce yourself on this forum thread. I'd also encourage you to add a real picture as your avatar because it helps build community!

It sounds like you are using ODK-X to build a survey and need to make the date of birth constrained to less than the date of the survey. You'll be able to do this with a constraint, which are described here in the documents as an optional column: