Create Ubuntu Live USB Drive From Ubuntu ISO Image Or CD Drive On a Windows PC With Ubuntu Live USB Imager  

1. Firstly, you will need to browse ISO image or CD/DVD source.

2. Then you choose the USB Drive connected to your computer on which you want to install Ubuntu with ISO / CD / DVD image as source. 

3. Now, select the size of a persistence file which will store the documents you create while using the Live Ubuntu.

Note: There are various persistence file sizes ranging from 128MB to 4096MB you can select as per your thumb-drive capacity.