How to allow PDF file uploads on iOS?

You must remove image/* and the other image/ file types.

<form action="" enctype="multipart/form-data" method="post">
   <input type="file" accept=".heic, .hevc, .heif, .pdf, .png, .gif, .jpg, .jpeg, .doc, .docx, application/msword, application/pdf" multiple>
</form>

Here is a sample of your code with my corrections: https://codepen.io/VladimirButakov/pen/XvXxGq?&editable=true

I made a web page that can get pdf files and send them to chats over a telegram bot. I opened the web page from my Iphone and just selected a pdf and sended it and it worked just fine.

The code I used for the input file is the following.

<form action="inviapdf.php" enctype="multipart/form-data" method="post" class="inputfile">
<input accept=".png, .jpg, .jpeg" class="bott" type="file" name="pdf"/>
<button>SendPDF</button>
</form>

I have an Iphone 7+ with latest IOS release. If I didn't answer your question can you be a bit more specific about it? thanks