Can I use an apple id on one phone

Yes, just remember that in doing so you are creating a completely new identity as far as the Apple system is concerned, but in the context of your needs this makes sense.

Apple ID Frequently Asked Questions - https://appleid.apple.com/faq/#!&page=faq

Click here to see how to 'Create an Apple ID' = create an Apple Account. --> https://support.apple.com/HT204316

You can do some sharing this way but again, if you are trying to set up a separate identity for business purposes and financial accounting you may not want to do this:

To learn how to 'Set up Family Sharing', click here --> https://support.apple.com/HT201088

You can only have one ID on a phone at a time. You can create a new one but sometimes it can get messy with things such as apps downloaded under a previous Apple ID. I have an iPhone I was given and for various reasons I didn't end up erasing it first and I haven't had any problems (I didn't keep the old apps). In your case it may be handy to do it this way which is not what Apple would advise but would be handy since it would allow you to quasi-transfer things such as contacts you may wish to keep for business purposes. If your sign in with a new ID on a device that has an old one then you will get asked if you want to keep information already on the device. The thing is, you'll also need to methodically go through all the settings and make sure that you update them all for your new ID.