The business side of REP

Looking for recommendations here. Looking to start real estate photography, I have my gear ready to go. however I'm looking for more information/advice on the business side of things. What do you use to schedule clients? send invoices? collect payments? send images? Do clients sign a contract or an agreement? any templates? I've watched a ton of youtube videos but most of them focus on shooting and not the business side of things. Any help or even masterclass recommendations will be helpful. TIA