In order to Set Maximum Upload File Size Limit in CformsII one need to perform below mentioned steps:
1) Login into wordpress admin area.
2) Click on CformsII -> Form settings.
3) Select the form for which one need to Set Maximum Upload File Size Limit.
4) Click on File Upload settings.
5) Apply the file size in KB in “Maximum File Size in Kilobytes”.
6) Click on update settings to apply the changes.