Before making the DNS change I would recommend testing your website with your hosts file.
You can edit the hosts file on your PC to bypass the DNS lookup and access the site on your Digital Ocean server through your main domain rather than the droplet’s IP address.
This only affects your PC and visitors to your website will see the site as normal.
The location of the file is as follows:
Windows PC c:/windows/system32/drivers/etc/hosts
Mac OSX /private/etc/hosts
Just open it up in your favorite text editor (e.g. Notepad) and add that line on the bottom:
Your.Droplets.IP.Address yourdomain.com www.yourdomain.com
Make sure tho change the
Your.Droplets.IP.Address with the actual IP address of the droplet and the yourdomain.com part with your actual domain
Once you have made the change, save the file then clear your browsers’ cache and browse to your website as normal.
You will see it served from our systems and will be able to test the full functionality of your Wordpress site.
To view the site on your existing host, just remove the line from your hosts file. If everything is working as normal, then you can proceed with the DNS change and point your domain to the Droplet’s IP address.
Also I would recommend following this step by step guide on the Digital Ocean website on how to migration your website with zero downtime:
Let me know if you have any questions.