As you may know, Microsoft Forms is one the lightweight form capability available on Office 365.
A new question type has just been added to Microsoft Forms (roll out is expected to be completed by end of December 2019): file upload
With this new field type, you can let respondents to upload file when answering your form Forms.
Personal form (aka not shared) will save the uploaded files into the user’s OneDrive while Group form will save it to a SharePoint site
To start using this new field type in your Forms, add a new question and open the More option to select File Upload
The first time you will be notified that a new folder (Apps\Microsoft Forms)will be created in your OneDrive to save the uploaded file.
Then below this Microsoft Forms, a new folder will be created for each Forms you are using the file upload option, which then will contains a folder for each ‘file upload’ question
Then you define some limits (maximum number of files a respondent can upload, the single file maximum size or the allowed file types [predefined]); to display the File Type configuration option you need to open the More settings for the question menu
If a respondent is uploading a file which already exist, the system will append the file name with an iteration number
NOTE this feature is available for both Forms and Forms Pro, but can not be used if the form is shared externally