Another great tip is to make a quick video or include written communication with the email that goes out with the link sharing what to expect and how they should complete the online form. 

For example:

Here's the link to the online form we discuss.  Prior to completing the online form please get your financial documents in order, your logins to your computer and/or phone information so you can complete the questionnaire in one setting.  

If you find you cannot finish all of the sections, please advance to the end and hit the finalize and submit button so the system can send me the portion you completed.  We can then complete the rest of the information when we get together for our meeting OR you can start the form all over again for completion. 

For your security we cannot resend your existing questionnaire as the server erases the input data every few hours for your protection.