My friend has been using commend bot and he provides commending services.
Many people come and buy commending services from him to get green trust factor so in this guide, I am gonna break the science of commending.

People use commend bot, it's a program to send 100's of commends from the bot accounts.

There are many online services by using you can generate bot accounts.

Commendation is something like you promoting someone for his work and guidance and CSGO gives weightage to it.
Yes, getting commends you can get green TF.

But here's the problem.

if you get commends from accounts which haven't played cs: go even once (bot account), do you think you will get any benefits from it?
Well here's the fact, for some people it works and for some people it doesn't but definitely you get green TF if you're getting comments from regular active accounts.