How to send an image and some contents using multipart form post request

Hello guys,
Need some help I am currently working in Xamarin app for sending data to server like some string and multiple photos I have used plugin.media for getting photos and I store it's image path to MySQL db now I can't find any relevant content on Google for sending image and string data in same api what I found is convert image in to base64 byte arrays and send it to server but I don't want to convert in byte arrays I want to send image directly from my mobile storage to server like in postman does is multipart form data
Any would be appreciated
Thanks in advance