The 140-character limit for Tweets can leave you with too little space to cover a topic. You can get round this by posting a Tweet with a link to a document that's already online, such as a PDF. Note that you can't upload a document from the storage on your own phone, computer or tablet. You can only link to a page that's already online. Twitter has an automatic web-shortening service which will make your link 20 characters long, even if it is shorter than that, leaving you 120 characters for the rest of your message.
Go to the webpage where the PDF file you want to add to your Tweet sits. Copy the address of the page from the address bar.
Open your Twitter page on your phone or other device. Click in the "Compose new Tweet" box and write your message.
Paste in the web address you copied earlier. Press "Tweet" to post your message.