If you would like to invite your clients to your portals in bulk, this article is for you. To access the this feature, go to a portal group of your choice, and click on "add Portals in Bulk" option on the left:

You will then enter a data uploader and mapper, which lets you drag/drop or upload a CSV file and map your data into appropriate columns. Use 'example csv' button to download a template. Columns that have a 'tick' in the 'required' column must be mapped, other fields are optional.

After you drag/drop your file, map the fields and enter an optional welcome message, you are ready to start the process of (1) creating the portals and (2) inviting your clients:

When you are ready, click the "Import" button.