The Signeasy app supports document sizes up to 40 MB.
Just a couple of things to keep in mind when in regards to document size:
Most email providers limit attachment size to 25 MB. Attaching documents won't be possible if the size is larger than 25 MB.
Larger document sizes may take longer to synchronize across your devices or save as drafts.
Be careful adding images, as they can quickly add to your document size.