By default SSH is disabled on Raspberry Pi (for both if you setting your own or bought the RPi from us).
To Enable SSH:
Open "Raspberry Pi Configuration"
Select "Interfaces" tab and change SSH to Enable
Go back to "System" and Change your password to something secured and you know.
If you create your own SD Card, default Raspberry Pi password is "raspberry" and it's not secured at all.
If you buy devices from us, you need to change the password to something else to use SSH.
After that you can SSH into your device.
You can read more about SSH here:
If you have further questions feel free to contact our support team.