How can I legally and efficiently help my girlfriend build equity by helping with a mortgage?
I'm looking for something simple, legal, reasonably formal, easy to setup and tax efficient. You just described marriage. Get married.
Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
How can I legally and efficiently help my girlfriend build equity by helping with a mortgage?

### Response:
I'm looking for something simple, legal, reasonably formal, easy to setup and tax efficient. You just described marriage. Get married.