depends on the project and sophistication of the sub...
1. Plan and spec
2. Written SOW w bid form
3. Some subs can receive via email,some text, some hard copy.
4. Walk thru with verbal direction.
5. I use google drive.. lots of paid options including builders trend, coconstruct, etc.
6. In addition to scope of work you should walk them thru your expectations, job site clean up, safety, handling materials, assisting in take offs if needed, recommendations, work hours, crew size, duration, schedule, payment, payment process, warranty, equipment operation, etc...
Thank for all of that @Emilio Ramirez... my husband and I build a few investment houses every year. We have noticed that communication between the GC/Subs varies drastically depending on the trade, level of sophistication, whether they speak English...etc. Some jobs are sent over email, some just communicated with a call (which leaves the door open for miscommunication). I am just trying to get info on how other people handle it, to see if there is a way to streamline the job communication without using one of the larger construction / PM software tools that none of the subs will likely use.