These are the days of Emergency Remote Teaching (ERT), when many teachers find themselves teaching from home, with classes of learners who are also in their own homes. If you're teaching synchronous classes using Zoom or some other system, you can still use a learner response system (LRS) like Captur Paddles.
One low-tech option is to ask your students to draw large, bold letters on pieces of paper. Give your multiple-choice question, and ask students to hold up their papers to answer. If you're on Zoom and have the gallery view enabled, you can see many students' answers at the same time. (Students could also print out our Captur Paddle PDFs, but not all students have access to color printers at home.)
A fun (yet anonymous) option on Zoom is to use polls. You can create a single poll in Zoom with A, B, C and D answers, and re-use that poll every time. (Note that in Zoom, "multiple choice" means that the students can choose multiple options; your poll should be "single choice" if you want students to only choose one of the A~D answers.)
Another option is to use Kahoot!, which gamifies multiple choice by awarding points to students based both on accuracy and speed. While Kahoot! can be really fun in the classrooom, there could be inequities using it remotely because some students will have more lag than others, and some students may be using only one mobile device and they would then lose time switching between screens.
Another online option is Nearpod, which lets you combine a number of activities that students can do on computer or smartphone, including polls, matching tasks, and comments, all of which are anonymous to other students, but the teacher knows which students are participating. Nearpod also has a fun game similar to Kahoot, but with a graphical representation of students racing each other up a hill; points that are based on accuracy and speed correspond to how far you get.
Google Forms can also be a way to give quick surveys or quizzes. Provide the students with a link to the survey or quiz, and give them a short deadline to go imput their answer, and come back to the class meeting.
These quick checks of understanding help keep the students engaged in your lessons. However you choose to do this, we hope you can use some of the activity ideas that we have posted on our site.