You can know the number of people who accessed to your Wiz in two ways. 

1. Know the number of people connected live 

In the Run section, you can find a counter, which indicated the number of participants on your Wiz live. It is displayed right before the maximum number of people you can host on your Wiz at any time. 

2. Access the detailed statistics of your Wiz

To access the information related to your Wiz after a meeting, you can take a look at the statistics.

1 - Go to Configure > Analyzer > Overview

2 - Click on View details on the Participants section

3 - See the split of anonymous versus identified participants (who signed their contributions)

4 - See the participation rate (ratio of active participants among present participants). Note that a participant is considered active when he does at least one action (send a message, answer a vote, react on a message, etc)

5 - This table allows you to know, among the identified participants, those who have participated the most (based on their activity on your Wiz)

Note:

A participant who accesses your Wiz from two different devices is counted twice, unless he is identified on both with his Wisembly account. And a participant who accesses your Wiz twice with the same device will be recognized and counted only once.