Hello dear,
If you have registered in the ICAI portal For CA foundation, then you can give 6 attemps of foundation exams of the next three years in May and November.
If you don't want to attempt this time then you don't have to do anything.
When the registration forms of the next attempt will out you can fill that form and appear for the exam.
Anything else you want to know ask in the comment section.
Thank you