Started to receive

[Talab1234]

“We have started to receive most of the information from the client”

Is this sentence grammatically correct?

Meaning we have most of the information at hand.

 

[Rover_KE]

It would be grammatical if you added a final punctuation mark.

 

[emsr2d2]

“We have started to receive most of the information from the client.”

Is this sentence grammatically correct, no question mark here meaning we have most of the information at hand?

If your meaning, as you stated, is that you already have most of the information, "started to receive" doesn't make sense. Say "We have received most of the information ...".
If you want to use "started to receive", say something like "We have started to receive information from the client. We have most of what we need".