Documentation
Increasing Craft's Max Upload File Size
If you're seeing an error that looks something like this when uploading an asset...
“<name of your file>” is too large....then chances are you're hitting Craft's default 16MB upload file limit.
Fortunately, this can be easily raised by either setting your project's maxUploadFileSize general config setting or by setting the CRAFT_MAX_UPLOAD_FILE_SIZE environment variable.
The value can be set to either an integer size in bytes or the shorthand byte value ending in K (Kilobytes), M (Megabytes), or G (Gigabytes).