You didn't give any clues about the services hosing your other two contacts lists, but if you want to import these to your iCloud list use the instructions in Import contacts into Contacts on Mac - Apple Support
Clearly you would need to go into your other services and export them to a vCard (.vcf) file ready to import them into Contacts on your Mac, then they would sync to your phone.
You could also import them your your iPhone Contacts but I've always found this a bit fiddly. Maybe I'm a bit old school. See Import contacts on iPhone - Apple Support
Before importing to iCloud I would also disconnect these other two services from your devices before importing them to iCloud so that there is no confusion about duplicates.
Even after importing them you might want to check the iCloud Contacts for duplicates, and this is the stage you can identify multiple contacts for one person and merge them.
Merge contact cards in Contacts on Mac - Apple Support