When you upload files (via any browser) or folders (only possible via Chrome), they will be immediately synchronized with all your other devices.
The first way to upload your files to your pCloud account is to click the Upload button on the top left. The Upload Manager will appear. To browse for files you need to click the File Upload section and then the Browse for Files button on the bottom left. Select what you want to upload and you are done. If you use Chrome, you can also use the Upload Folder section and then the Pick Folder button in the middle and upload entire folders from your computer.
Also, you can open the Upload Manager by clicking the Upload button on the top right of the web platform.
There is also another quick way for uploading files - the Remote Download feature. When the Upload Manager appears, you can see the three upload options - the File Upload (by default), Folder Upload (for Chrome only) and the Remote Download. If you switch to Remote Download, you will see a Link Box where you can paste any file's URL and upload it directly to your pCloud. To do so, choose a file, copy its URL, paste it in the Link Box and click the Upload button.