Export your entire client list
Go to Admin>Clients
Click the blue "Options" button>Export as csv
Remove any unwanted columns from the data sheet and upload to your marketing software.
Export a segment of you client list
E.g. a list of new clients from the last month
Go to Marketing>SEGMENTS>New segment.
Name the segment and enter a description if desired.
Create a rule as shown in the screenshot below but choose the date rules as required.
Save your segment and see it in the segment list.
Click "Options" to the right of your segment>Download csv
Remove any unwanted columns from the data sheet and upload to your marketing software.
Click "Client count" to see how many clients match your rule