How do I do it by mail?
Fill out a VA Direct Deposit Enrollment VA Form 24 - 0296 .  You can Download VA Form 24 - 0296 PDF and mail in the completed form.
and also do I need to inform you of other changes in my life that could affect my compensation or do you guys know somehow?
If you have a disability rating of 30% or higher. You may be able to add eligible dependents to your VA disability compensation to get a higher payment. Find out how to add eligible dependents