You may want to increase the max upload size on your WordPress installation in order to upload a custom theme or larger media files.
Note: This will not work on shared hosting plans. This workaround is only for self-hosted WordPress installations.
From your server, access the php.ini
file under your PHP installation directory.
sudo nano /etc/php/<php_version>/apache2/php.ini
Find and replace the following lines with the correct values
upload_max_filesize = 64M
post_max_size = 64M
max_execution_time = 300
Restart apache to apply the changes
sudo systemctl restart apache2