Stop before you go down the google route GBM. How about
Dropbox they will be a little more secure than google. Sign up for the free service and simply use it for scenarios like this, but pleases be aware that anything you don't want shared with a 3rd party should first be encrypted before transfer or at least buried (Russian doll) and password protected.
First off what type of file format is it and what size? If a jpeg format for example, then it can be compressed more before zipping, the same for a lot of other formats one way or another or even converted to a different format. Don't forget to send a friendly format that the person at the other end can easily open/view. I hate it when someone sends me a .doc (MS Word) file. I would not insult my Mac with MS Office being installed

So therefore will have issues opening the file. Not only that, but if you sent a .doc created and saved from a later version of Word on a PC to another PC user or Mac user for that matter,and that person the other end has an earlier version of Word. They will also have issues opening the file. Convert/Export as a PDF first Please. PDF = Portable Document Format meaning that anyone whether Mac or PC and no matter which software's they have installed can open and read the file. I've gone a bit off course there but never mind, hopefully you will learn something.
Most email providers will limit you to 5 mb so anything bigger than this you can use the cloud (google drive, dropbox or whatever) and then email the download link to the person in question.
Onto compression, without going into to much technical detail

, there are two types of compression, Lossy and Lossless. Using an image as an example, Lossy compression works by trashing bits (literally ha ha) out of the file. So in the case of the image it takes pixels out of the image, hence the smaller file size and worse quality picture. Lossy = sacrificing quality for smaller filesize. The there is Lossless compression which works by squashing/squeezing the file smaller to fit so no loss in quality. It's gets squashed and then un-squashed when de-compressed. Both types have their pro's and cons depending on ones uses.
There are various formats of compression (zip, rar, tar, gzip, 7zX to name a few) for various uses, security, archiving or sending across a network for example. Some compress more than others. But in your case .zip would most likely be fine for your needs. Personally I would zip the file, then put that zipped file inside a folder as a container, then compress the whole lot into a password protected rar file or better still a dmg. Then give the fie some obscure random name (hg5gh749v4) make a note of it so you know the name and what's inside the file. You could even go as far as encrypting the file before transport too. Once complete you then upload to the cloud or wherever.
The likes of filesharing sites and other cloud based services that offer free services including email will have bots that scan their servers, nosing into what's stored on them, gathering your personal data (whatever you have uploaded/sent) to do as they please with. These services are not free your selling yourself. Compressing like I said and password protecting will protect you somewhat from the bots being able to see inside and steal the contents. They would most likely be able to see inside a bob standard non password protected zip file and some may even be able to see inside a password protected zip.
As to which compression software to use I shall leave that to the windblows users to advice.
(:-})