Adding a new line without needing to set the parameters for sum or copy paste information from rows

hello, sorry if this is a bit too basic of a question, but ive only used excel 2 days now and therefore ive been struggling with understanding how exactly it works. Ive been asked to digitise the inventory for my workplace and even though the data is easy enough to gather, its all split across multiple batches with different expiration dates. I know that to add a new line i need to press ctrl,+ but when i do i need to

• half the time reformat the cells with the same look as the ones im actually trying to emulate (FIG 2)
• copy paste the information on the cells (FIG 2)
• reestablish which cells the sum draw from (FIG 3)

which is fine and good, i can do that each time, but my position here is temporary and im gonna have to hand over the excel sheet next month, and the people i work for find the use of email and pdfs "tech savvy" so if i dont find a way to make it easier for both myself and them its gonna be back to pencil and paper.
I tried finding other ways of going about it like at least creating 5 cells for each product that way they have a surplus of cells and they dont have to add any new ones, but that A) looks bad B) bloats the size of the excell sheet itself.

Thank you in advance.

fig1

fig2

fig3