Hi Vaishali,
- You will need to create an entity with 1 object for each value.
- Associate this entity to the entity you want to select string values for. Then you can use the Simple Checkbox Set Selector from the app store to let the user pick 1 or more values.
- Add boolean attribute in entity, add condition in microflow to check weather it has value or not based on the value change the value of boolean attribute to make the checkbox selected.
Hope this helps you!