You can easily add your Spacemail address to the Gmail app to manage your email address using your mobile device.
To do this,
Open the Gmail app.
If you are not logged in to your Google email address, select “Add another account”. If you are logged in to your Google email address, click on the user icon at the top right of the screen, select “Add another account”:


Select “Other (IMAP)”:

Enter your Spacemail address and click Next:

Incoming server settings:
Username: your Spacemail address
Password: the password for this account
IMAP Server: mail.spacemail.com
Port: 993
Security type: SSL/TLS
Click Next:

Outgoing server settings:
Username: your Spacemail address
Password: the password for this account
SMTP Server: mail.spacemail.com
Port: 465
Security type: SSL/TLS
Click Next:

Finalise the Setup: You may be prompted to set up your account name (for display purposes) and other personal settings.
Enter your name and click Next to complete the setup process:

Your Spacemail email address is now added to your Gmail app, and you'll be able to send and receive emails from that account directly through Gmail.
That's it!