There is a different tab for page access, right next to the microflow access tab.
If pages/microflows are not shown: are you sure that one is able to navigate to these pages via a microflow/ button or navigation?
Hope this helps!
Do you mean microflows? If not then you need to look at the ‘Page access’ tab on the left.
If you open a Microflow and then click any white space inside it. Then click the properties panel on the right hand side you should be able to set the access there also.
Then I believe it will appear in the security for you.