I buy Standard 10GB package and cant add more than 1 user for email account. 

Here:

https://www.zoho.com/mail/zohomail-pricing2.html

For free users: 10 users

Standard: No limits

How i can add more users? I have more domains and 1-5 email adress for every domain.

I dont know... every time a get message:

Max user license limit reached. Please purchase/upgrade license to add more user(s) with mailboxes.

Sorry for my english...