My EmClient account settings for Google Gmail show the SMTP port as 587 and the IMAP port as 993. Is this correct and where do you easily find the email send and receive port numbers for any email service provider? Thanks!
Yes it is correct for gmail.
For the other providers I Google search or go to the provider’s site to see informations.
If it is working then it is correct 
And like user FranceBg has written best site to find these information is your provider’s support site.
Jan