I'm with Grelber a lot more information is needed.
Using standard compression algorithms such a Zip, 7Zip, RAR, etc a 50% or better compression ratio is possible with pure text files, but if there are lots of graphics and/or audio it is entirely possible the compressed file will be larger than the original. Text compression algorithms like Zip, 7Zip, RAR, et. al. compress data by identifying repeating character strings in a segment of text and substituting pointers to the original string instead of repeating the string itself. Graphic and audio files have few or no such repeating strings and therefore are not compressed by these algorithms. In fact many compression utilities simply copy graphic and audio content rather than trying to compress them. Graphic and audio compression algorithms like JPEG, MPEG, ETC. are lossy and achieve compression by physically discarding some/much of the data which, of course would be unacceptable for text.
My solution for this situation is to place the data file in a public folder on an internet server and share it with the intended recipient(s). That handily gets around any email size restrictions/limits. You simply send the URL and the recipient downloads the file.
