Hello there, line. Thanks for posting here in the Community space. Let me give you insights into adding PDF bills in QuickBooks Online (QBO).
When you said about adding PDF bills, did you mean adding PDF attachments on bills or uploading PDF bills in the receipts tab from the transactions menu? If so, please note that we didn't receive any of the same issues you're experiencing. With this, I recommend performing some basic browser troubleshooting to rule out the possibility of having issues with your browser. Know that browsers accumulate temporary internet files that can affect your browsing experience. Too many internet files can sometimes change how your QBO company behaves, resulting in errors when performing tasks. See the following keyboard shortcuts for suitable browsers to open a private window: