There are no dedicated mounting holes as such so you just add extra pads to the footprint to use as mounting holes.  They should always be the highest numbered pads (last to be added).

Where mounting holes are "land-less", you simply create a pad style which has a drill hole larger than the actual pad itself, or set the pad size to zero. Easy-PC will allow you to do this but will give you a warning that the drill is larger and thus completely removes the pad 'land'. This is only a warning to make you aware and can be ignored.

If the mounting hole is for a conductive fastening, such as a setscrew, it can be a good idea to deliberately design the mounting hole with a relatively large pad.  This serves two purposes.  It creates a keep out area so tracks won't accidentally be shorted and provides a wear surface to protect the board substrate from repeated removal cycles.

Where mounting holes are for the board, not a specific component, they can be free pads but it's not essential.  You can also create them as pcb only components if they're likely to be needed for several different designs.  In this case you would need to use the 'properties' option to suppress them from part lists.

When including mounting holes as part of a pcb symbol (for instance, as part of a connector) you should ALWAYS ensure that they are the highest numbered pads.  If you've accidentally added them too early, use [Edit], [Renumber Pins] in the PCB symbol editor to correct the numbering.  The reason is that when editing the resulting component, there's an option in the [Edit] menu to [Neme Pins by Row/Column].  Part of this dialogue is an option to 'Ignore Last Pads' with a box specifying how many.  That assumes that the mounting holes to be ignored use the highest pad numbers.  It allows connectors such as the DIN 41612 range to be correctly identified by column letter and pin number.