As already mentioned in other answers you can't edit object parameters after they are created in Blender. After the creation process they become regular "static" objects and loose any "parametric properties" they had.
In an attempt to not leave you empty handed I'll try to present an alternative workflow: Be smart, use modifiers to your advantage.
If you foresee the need to adjust geometry after the fact, or edit parameters frequently, plan ahead, build your objects in a way that allows tweaking needed parameters easily.
This is where modifiers come in, they provide for what is often called "non-destructive modeling."
If you need to, say, easily change the number segments of a cylinder, or frequently adjust its height then it would be smart to rather than of adding a regular mesh cylinder build one with modifiers instead.
Create a simple single edge mesh with no actual faces, add a Screw Modifier to it, then a Solidify Modifier. You now have a "Parametric Cylinder" you can easily adjust the number of segments and height of. Just control parameters from the modifier stack, replace single vertex with an edge and now you have top and bottom caps.
This is what is often called a "non-destructive workflow", where modifiers are kept "live" so they can be easily edited.
This will obviously not work every time nor for everything, and you can't always achieve every end goal without some destructive steps, but be inventive and you can go a long way.
Use modifiers to your advantage, extend this to other tools like constrains, drivers, shapekyes etc., and you can go a long way in creating easily editable "parametric objects".
Here is a "Parametric Sphere" made from a single vertex mesh and two Screw modifiers.
You could even control radius with an additional Displace Modifier"