JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
You can use the "File Upload" under the "Form Tools" section. You can follow this guide to learn more about it: http://www.jotform.com/help/332-How-to-create-upload-forms. You can also see other suggested widgets for file uploads there.
If you want to limit the file types, like let's say to images only, you can do that by following this guide: http://www.jotform.com/help/29-Upload-Field-Allowed-File-Types
Please also do take note that accounts have an upload storage space limit, submissions with file uploads will take this space, please check this guide: http://www.jotform.com/help/33-Changing-the-Upload-Size-Limit. Also, please check our pricing page to see the upload space storage limit of each plan.
Do let us know if you need more information on this.