You can use the Chat+ tool to allow in-person and virtual attendees to engage with content together. Virtual attendees will see the Chat+ to the next to the component right on your website. For your in-person attendees you will create a custom link that gives them access to Chat+ features. This is done by adding "?hybridMode=true" to the end of your Sequel embed link.
For example, https://embed.sequel.io/event/12345 would become https://embed.sequel.io/event/12345?hybridMode=true
You can also use this link to create QR codes for your in-person attendees.