How do i switch between my childs profile and mine on ipad

iPads (and iPhones) are designed to be used only by one person. Only macintosh computers support multiple users. That being said, you can approximate this environment via the Screen Time function. You can lock certain applications behind a pass code that your children do not know. You will not be able to enable/disable individual mail boxes, though, so don't put your mail boxes on the iPad.

Good luck.

Unlike other computers with which you may be familiar, that support multiple user profiles - other than “managed” educational environments, OS/iPadOS devices are not intended to be shared.

Be aware that if you sign-out of iCloud and other Apple services - and allow another user to sign-in with a different AppleID - you’ll not be able to change back for 90-days. This restriction, intended to prevent account abuse, cannot be bypassed.

Unless you fully understand and accept the implications, you would be well advised to reconsider attempting to share an iPad between users with different AppleIDs - and neither is it wise to consider sharing a single AppleID between users. An iPad is principally intended to be used by a single user with a single AppleID.

An iPad is not a multi-user device. It does not support multiple user profiles.