Hi @tanzilhuda,
Backing up with what @bernieseville have said you could do the same as shown in the image below:
In the survey sheet of the xlsform:
Note: With this expression you will not be able to enter 00, hence integer between 01 to 99 are only accepted.
Reference xlsform:
Regex_Constraint.xlsx (10.0 KB)
GOOD DAY!