How to enter service items and price since they are not inventory items

We run a small clinic and we partner with institutions who run labs and scans for us. i do not know how to enter the services which is the scans and lab test we offer along with the cost price to us and the price at which we offer to our client since we do not do the various tests ourselves.

you can create non-inventory items and set their purchase and sales rates.
read this guide Create non-inventory items | Manager