Can I upload two or more CSV files simultaneously with the help of some APIs or services or apps?

Hi Mohit,

I don't think this could be done using the standard functionality, So you could try using a app (Like EasyUpload Attachments (Free) , Cloud Drop , etc ) for the same.

Apart from this I beleive Data Loader could also be used to upload multiple attachments.

NOTE: To upload attachments:
Confirm that the CSV file you intend to use for attachment importing contains the following required columns (each column represents a Salesforce field):
ParentId - the Salesforce ID of the parent record.
Name - the name of the attachment file, such as myattachment.jpg.
Body - the absolute path to the attachment on your local drive.

Hope this helps you.

Thanks