Flex uses SharePoint List Columns which include many different options. Some column types are not available to be changed once created so give consideration to the type you select when setting up.
Text
Text columns (single line) are probably the most common – there is also an option for multiple lines of text.
The type of text chosen allows for more functions for the users. If the text requirements are basic then use Single Line as it is less cluttered.
Text fields make filtering a bit more challenging.
Yes/No
This is a limited use column since the only option is Yes or No. You may wish to include a Maybe in the answer in which case use a Multiple Choice column.