Hi guys this is my first question here...
How many tyoes of patching are there & how we perform different types of patching?
And what are the exact steps to do patching in redhat,fedora & ubuntu server?

Depends what you mean by "patching"

You can report a bug to any of those distributions and they will fix the bug or pass the bug report to whoever maintains that particular software package. When the bug is fixed the fix will be included in the updates that the distribution sends out now and then through their package manager.

All distributions are required by the GPL to make the source code available for any open source program that they distribute. You can download the source code and patch the software that you are concerned about yourself. Note that this isn't necessarily a bug fix. It could be a new feature that you want to add to the software. Then I would suggest that you submit the patch to the person maintaining that software and ask them them include the patch in the software. If they accept the patch then you won't have to maintain the patch as new releases of the software in question come out.

The differences in the three distributions are in the package manager they use. RedHat and Fedora use the RPM package manager. Ubuntu uses apt-get. By this point in time all of the package managers have all of the possible features that you could conceivable need in a package manager so which package manager you use is a toss up.

Welcome to LQ,

There are other concepts of packages, but the one I know is a .patch file where you apply it to sources. It is text readable, where it specifies adds and deletes to source files. You also can use a dry run option to see the changes before the patch command really applies the changes.

That's the type of patch I know. As I say there are others, like ones to update "patch" your system, but I've never used them.

rpm equates to dpkg, not apt*; dnf equates to apt*. rpm & dpkg are base level package managers, for installing, removing and database management. dnf & apt* are high level command line package managers, that perform searching, resolving and fetching functions among others, and calling on the low level managers for actual installation and removal.