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Hi Sivanesan,
Thank you for posting your question in this community. Based on your description, it seems that you are looking for some source control tool to track the changes in source code during the development workflow in SharePoint designer.
Because, this community is majorly focusing on the built-in feature of SharePoint Online. I suggest you can raise this question in TechNet community under SharePoint category. Some experts of code development with SharePoint designer may give you some suggestions in this scenario. Thank you for your understanding.
In addition, I also found some related information about Source Control with SharePoint Designer. You may have a look at your convenience.
For your information:
Sharepoint, Sharepoint Designer, and Source Control
Using TFS and SharePoint Designer
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Best regards,
Dihao