How to Configure heroku application DNS to Godaddy Domain?
Step 1
Login to heroku command line terminal
Run the below command
heroku domains:add www.yourdomain.com
heroku domains:add yourdomain.com
Look up the Heroku-supplied DNS target for the custom domain which you use using the heroku domains command
or you can check this by logging into heroku dashboard --> Settings and you will find this “Domains and certificates” section.

Step 2
Configure your Domain name DNS provider to point to the Heroku-supplied DNS target
On GoDaddy Go to "Domain"and create a CNAME as a record as shown below
In the below example my heroku application name is boiling-bayou-***.herokuapp.com
Host: www Points to: boiling-bayou-***.herokuapp.com

Below is the screenshot of heroku application name in heroku dashboard. You can find your's here.

Step 3
In the below section, Replace “avian-earth-***.herokudns.com” with your own Heroku supplied DNS target in GoDaddy
Add this as a CNAME in DNS records
Host: yourdomain.com Points to: avian-earth-***.herokudns.com
Repeat the same by replacing with your another DNS target
Add this as a CNAME in DNS records
Host: www.yourdomain.com Points to: www.***.herokudns.com
You can find below the sample records for your reference

How to send naked domain to www in Heroku/GoDaddy?
On GoDaddy, use the "Forwarding" feature to setup a forward from yourdomain.com to www.yourdomain.com.
Click "Manage" under "Domain" in the "Forwarding" section to add forwarding details.
In the “Forward To” section provide www.yourdomain.com
If you want to redirect your naked domain “yourdomain.com“to “www.yourdomain.com“
Follow the same configurations as seen below.
Note: wait for some time so that DNS can propagate
