Since the domain name is bought from Wix the DNS zone should be controlled /edited from there. What you need to do is to point the A record of the domain name to the IP address of your droplet.
You should be able to make this change from Wix’s control panel:
Editing DNS Records in Your Wix Account
Go to the My Domains page. Note: If you have more than one domain in your account, select the relevant domain.
Click the Advanced tab.
Click Edit DNS.
Edit the relevant records,e.g
point the A record of your domain to the IP address of your droplet
Click Save DNS.
Let me know how it goes.