some people print out the first page. it might be a good idea to keep all the manuscript files. I didn't. and later i wanted to print the first page of the reviewed manuscript but could not do it. eventually I did not submit it and my petition is still passed. if you do decide to print the first page, keep all the files.
h*1
4 楼
Invitation letter and thank you letter. also You might want to keep all the manuscripts to show the countries where the manuscripts come from if you need