How do I price a office cleaning quote

Hi, I'm starting my own cleaning service and I don't know how much should I charge to clean houses

One would have to hope or assume you have worked in this industry working for someone else, how much do they charge,

Find some companies in your area getting this done and just ask them what they pay.

And in general you "estimate" how much time it is going to take, that the pay is to be, what the costs are, and estimate.
Remember as a private contractor, you are liable for your own taxes including yourself employment taxes, so for a rough est remember about 30 cents of ever dollar you take in, will go for taxes.