You really do need to properly prepare the iPad before allowing anyone else access to the iPad. Otherwise you will have a very real risk of unintended merging of your personal and sensitive data with the next AppleID account that is used - and very likely encounter issues with Activation Lock.
As already suggested by Rudegar, you need to follow this process:
What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
Having correctly prepared the iPad, you can set-up the iPad from the initial “hello” screen.
Your child should have their own AppleID - in fact, every user should have their own AppleID to use with their own devices. This is essential to maintain intended separation of activities and to avoid unintended sharing of sensitive and data. Done properly, you’ll not have any issues with content related to your child appearing on your own devices - or your data appearing where it shouldn’t.
You may find this information to be helpful with setting-up an AppleID for a minor - and considering appropriate controls:
Apple for Kids - Official Apple Support
Help your child set up an iPhone, iPad, or iPod touch - Apple Support
Family Sharing and Apple ID for your child – Apple Support
Use parental controls on your child's iPhone, iPad and iPod touch – Apple Support