Step 1 : Sign In to Marketplace
https://www.notion.so/cstechmk/How-to-Setup-Your-Marketplace-6a9316c5f655479180dc1a621535b4bd#332a57a313d44a04ae54710ce9ed8061
Step 2 : Mouse Hover on Master
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Step 3 : Click "Product Attributes"
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Step 4 : "Main Attributes" Page is seen , Where you can Manage Attribute Values, Edit , Hide/Show Attributes
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Step 5 : Click the icon shown in image to make changes
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Step 6 : Attributes can be added or edited
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Step 7 : Click "Custom Attribute"
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Step 8 : By Entering Name , Selecting Type and Sequence Id , you can create new custom attribute.
you can EDIT / Delete Custom Attributes