The brief, in plain words
Describe what is eating your time. Plain words are enough; the written reply tells you which service fits, what it costs, and when it lands.
Scope in writing
The written proposal is the contract. Prices, dates and decisions exist in a thread you can search later.
Progress in writing
Build updates arrive in the same thread. Questions come batched and are answered the same way, so nothing depends on anyone's memory.
Demos, recorded
You watch your system working on video. Rewatch it, forward it to a partner, decide at your own pace.
Handover on the record
Code, accounts, keys and plain-language docs are handed over in writing, alongside every decision made along the way.