Create form or app to automate quote and invoicing with sheets.

I own a small window caulking company. I seal cracks around windows. My service charge by linear foot + product used. I take measurements with my pen and pad along with client info and might do 4-5 clients a day. Arrived at home I calculate the amount of (caulking in linear feet + price of service time). I transfer my notes into a Google Sheet, I use a template to create line items for my quotes. Then save as pdf and send via email. My idea is to create some sort of form or app I can fill out on site with the client. The completed form would then send client information and measurments to a spread sheet in "sheets" for invoicing or quotation. Also I'd like to be able to add individual openings (ie:windows or doors) as line items and sum a total. These can be individually parsed into rows in sheets. im guessing this is where calculations quotes and invoices would happen. Linear feet added with hourly charge or base price +taxes. Here in Quebec we have 2 taxes. Ex: Subtotal + tax1 + tax2 = Total price. Then I could simply share the sheets or send it via email without editing access. Basically minimize my work and automate the transfer process. I have a smartphone and iPad I can use on the field. I do not want to spend alot of money. I know there are multiple companies who create forms for invoicing. But they cost alot monthly and/or I'm forced a watermarked template on my invoices. Not only that many companies do not offer 2 types of taxes. This is a special situation here in Quebec. Thank you.