can I merge to Apple ID accounts to one?

What the Ghost said is true you cant merge two apple ID

You can archive a lot of what you store in iCloud and move it to another account.

Archive or make copies of the information you store in iCloud - Apple Support

Any purchases you have you cannot move at all.

No, I am sorry. It can't be done.

You can try setting up Family Sharing between the IDs if you want to be able to share purchases made with the IDs.

Family Sharing. https://support.apple.com/en-us/HT201060

Family Sharing - Set up. https://support.apple.com/en-us/HT201088