Problem
Recently faced a strange issue, where I need to create number of rows to a multiline field but Row Layout option was missing. I am going to share quick tip to solve this issue.

Solution
I faced this issue for the first time, never saw a multiline field without row layout option.

First I checked other multiline field and there I was able to see row layout as usual so I thought there maybe some issue with the field definition. Next I exported customization and compared field definition with other multiline field but I was not able to see any difference.

So I thought of creating a new field as I tested by creating another multiline field as well and I was getting row layout option. Next thing I checked how much data is available in this field and I was able to see almost ever record have data in this field, which means If I create new field I need to move data from old field to new field, not a difficult task, we can do that easily using different options.

But as I was using classical editor (now when you do customization within Dynamics 365 CE it is known as classical editor), I thought of trying new Power Apps editor to see what options are available there. When I opened entity form from Power Apps studio by navigating to make.powerapps.com. You can also navigate there by selecting Try New Experience button

I got following options,

After increasing field height I was able to see row increased in the field!!

So, before jumping any conclusion make sure you have explored all the available options.

Hope it will help someone!
Keep learning, Keep sharing !!