If you are asking about a Time Capsule......it cannot be partioned unless the drive is removed from the Time Capsule, placed in a separate enclosure, and connected directly to your Mac so Disk Utility can be used to set things up.
Then, you have to reinstall the drive again in the Time Capsule. This is not easy, and it will void the warranty on the Time Capsule.
Definitely not recommended unless you have done things like this before.
Much better to simply let Time Machine backup to the Time Capsule automatically. Backups will be kept separate for each Mac automatically. I have had 4 Macs backing up to the same Time Capsule in the past with no problems at all. Each Mac can only "see" the backups from that Mac.