The CTA has a big headline telling visitors in clear terms exactly what they should do (“Try Our Product”). The big button stands out and also clearly states what will happen when they click the button (“start now”).
First, Add the right Module
New modules can only be added inside of Rows. If you are starting a new page, don’t forget to add a row to your page first. Learn more about Rows here.
Use the visual builder to add a standard section (the blue +) and then section (green +) with a layout of your choice. The number of columns could be changed afterward.
Then add a Module Button to any part of the row.
Click the gray plus button to add a new module to your page.
Click on Call-to-Action

Add Content
Add Title: Under Button Text: Replace “Your Title goes Here” with your text
Add the Button Text
Add URL under Button URL: [enter URL] - The button won’t appear if there’s no link.
Select if you want to add link it in the same window or new one.
Add the text you want to
Select the background you’d like to add

Design Options
Under design:
Go to alignment and select the right Button alignment
Select the right color
If you want to customize the button, disable the Use Custom Style option
Use the following setup to customize: Button Text Size, Button Text Color, Button Background Color, Button Border Color, Button Border Radius, Button Letter Spacing, Button Font, Button Hover Background Color, Button Hover Border Color, Button Hover Letter Spacing
Add an icon to your button when you hover over it.
If you want to always have the icon in the button, disable the “Only show icon on Hover for Button” option
Sizing Options
Drag the border to the desired size
Or go to Design, under-sizing
Set the Width.

For more information https://www.elegantthemes.com/documentation/divi/cta/