Note -> Please take backup before applying patch
Step 1: Download the patch, as shown in the screenshot below according to your WHMCS version.

Step 2: Now from local go to the patch folder that you have extracted.
Step 3: After extracting the Patch go to the path as shown in the screenshot (\whmcs\modules\addons\ -> In local ) and (/modules/addons-> In server ) to upload the cloudx addon module.
Note : Please keep the backup of the existing folder in your local. Then start upload process.
Step 4: Now Drag the file to upload cloudx patch and override files screenshot given below.
Step 5: Now navigate to the path shown below in the screenshot (\whmcs\templates\orderforms\ -> In local ) and (/templates/orderforms-> In server ) and upload “cloudx_cart” orderform.

Step 6: Now Drag the file to upload orderform patch and override files screenshot given below.