To set a number of emails to be sent by Closely go to Email Outreach -> Accounts -> Daily emails limit. Please find our recommendations below.
start with 100 emails per day;
after a week increase this number to 300;
after another week increase it to 500;
continue increasing the number of emails adding 100-200 emails per week before you reach the desired number or the allowed maximum.
Here is what Google says: https://support.google.com/a/answer/166852
Of course, you are free to start with a higher number, however, if you have never run any bulk email campaigns from your email account, this might look suspicious and your account can be suspended for a period from 1 to 24 hours.
Microsoft is more strict in this matter: https://support.microsoft.com/en-us/office/sending-limits-in-outlook-com-279ee200-594c-40f0-9ec8-bb6af7735c2e
The maximum number of recipients you can add to a Closely outreach campaign is 5000. The number of emails in a sequence is not limited.