Steam Guard - protect the account through a unique code that must be entered when logging in from a new device. This option provides good account security against hacking. 

But on the other hand this is very inconvenient when your order an Rank Boosting in Dota 2. The booster will not be able to log into your account. Therefore, you need to turn off steam guard. However, there is no reason to worry about the security of your account. And that's why?

if you want to share access to another person, just activate the "family view" option. This functions protect your account by PIN-code and no one will be able to access to account settings.

HOW TO DISABLE STEAM GUARD?

1) First you need to disable two-factor protection. To remove two-factor protection from your account, open the Steam mobile app, go to the Steam Guard section and select "Remove Authenticator". Confirm the deletion in the confirmation window that appears by clicking "Delete Authenticator" again.

2) After that click Account and Manage steam guard in steam clinet

3) Click Turn steam guard off

Done, anyone can login into your steam account with code confirmation