More than one iCloud acct
How to get my other iCloud acct on new iPhone with new iCloud acct
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You can only have one ID as your primary sign in ID at any one time. It is possible to designate a second ID as one to use for App and iTunes Stores purchases but this will then disable the first ID from making any purchases with your primary ID.
More explanation about your situation would help direct you to a specific solution to your problem.
If you have app purchases split between two IDs, look into using Family Sharing. Set up Family Sharing - Apple Support