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.

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

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