Yes , sometimes error correction have to be made , but them must be allowed only to administrators not clients, so no misuse can be done. If no change is allowed by an admin anymore, that's will be translated in a credit note generation of the incorrect invoice and generation of a new invoice. I think that's not the right way of doing it.

So you want admins to be able to edit the invoice, and just re-cache an updated version of the invoice? Caching of invoice PDFs to disk will eventually use a fair amount of disk.

Invoices display a list of goods and services purchased alongside the total amount that a customer must pay. Important information such as the balance, due date, and payment status are in the invoice record itself. proofreading and editing services

Hi!
By default the invoice should be cached to disk (on initial generation).

If you want to implement editing the invoice, then i would suggest adding a "re-generate" button for the invoice. (So ppl that know what they are doing, can do it)

Generally:
A lot of Countries/Juristications have regulations against editing invoices that are sent out to a customer.
Local businesses here (for example) will generally leave the original invoice and then add a correction invoice/note. without editing the original one. (So: Wrong invoice amount (83 EUR) => Cancellation Invoice (-83 EUR) => New and Correct Invoice (45))

As tempering with invoices that are already sent out to a customer (via mail for example (default)) ends with the customer having two invoices for for 2 different amounts.

See https://smallbusiness.chron.com/fix-invoice-mistakes-80684.html for inspiration.

I would also like to add "fair amount of disk use".
The default invoice is around 80KB. Lets assume we add a logo and make it 200kb in total.
Lets assume 250 clients w. 2 invoices per month each. (500 invoices/month total)

2 invoices/client* 250 clients * 200kb => 100 megabytes /month in data gain.
12 months in a year: 1.2 gigabytes total per year
10 years: 12 gigabytes

shouldn't be an issue with most hosting services/plans.

Maybe set an invoice retention time ? Most countries regulations nequire to keep invoices for a certain amount of years. (usually between 7 and 10).
So you could add a limiter. And then remove historic invoices (older than the limit) from the system.
(remove from display in clientarea/adminarea, remove cached files)