Hello welcome.
Those are some very broad questions. Have a look around at some of the post here first then come back with a single more specific questions and you will find more responses.If you are starting mobile, figure out if you are going to be just offering washes or full paint correction. Interiors shampooing or not...... and so on. Perhaps you can offer just a few services like a wash and interior vac with window cleaning to start. Then add services as you financial and personal capabilites allow. I would suck to spend a ton of money to get everything you need for a full service and only find that it isn't for you.