Monogram is when you combine and overlap more than 1 letter to create a single form, normally 2-3 letters are used.
Monograms are very minimalist in there style which can be a good or bad thing depending on there business it is being used for.
Monograms can be dated back to as early as 350bc appearing on coins and by crafters to show ownership on their pieces of work.
Choose your letters you are going to make your monogram with. If this is your first time, choose your initials to start with.
There are many ways to create your letters:
You can draw them with the Pen Tool and create custom letter forms
You can create them using and editing shapes by manipulating anchor points
Or you can use a font, most fonts can work as a monogram + there are fonts made exactly to be used to create monograms.
Once you have decided what letters you are going to be creating you will need to change them into shapes to make them easier to edit and change around.
Select your letters - Object - Expand - Make sure all are ticked - OK


Now your letters have been turned into shapes, select them both - Right click - Ungroup
You need to make sure you can move them around individually
And finally select them both and align them over the top of each other

They will be hard to read currently just ontop of each other, It is a good way to separate each letter onto it's own layer, move the shapes onto their own layer and lock the layer you are not currently using.
To be able to manipulate the letter so they be both read select the 'direct selection tool' or click A on your keyword
Select the anchor points you want to pull on the D so that it can still be proportional, hold shift to click multiple
Now select the K anchor points you would like to extend with the direct selection tool

A nice effect on monograms is to give them the effect of being interwoven to each other.
You can accomplish this by removing certain points of the letters
Select both letters - Object - Path - Offset Path - Choose a size you feel is right to take off - OK
I like to base them off by knocking out one horizontal & one vertical off each shape
To delete the unwanted area's select your letters - Pathfinder tool (Shift M on keyword)

Hold the Option or Alt key to ****make sure you are minus them out if you do not hold option it will combine the letters together
Click the areas you want to minus out
Remove all other unwanted bits, leaving online the inward shape
To make it all one shape - Select your letters - properties - pathfinder - unite
To clean up and look at how many 'points' you have on your design on your keyword click - Command Y to view the outline of your shape
If there are too many anchor points you can try select your design - Right Click - Simplify - This ****will automatically try to clean up and remove unwanted anchor points (Just need to be careful with certain shapes as it might alter the shape or remove to many anchor points, experiment for what feels right for you
You should now have a finished Monogram that has a 3D effect looking like it is interwoven with the other letter. Play around with other letters to make your perfect custom Monogram!