My suggestion is to print or PDF your invoice you submit to Maritz for your own records.
Don't want to divert too much on the topic, but with every single assignment I perform, I ask myself these following questions to know if I have good documentation on a shop, for my own records and if I need to dig into the past:
Do I have copy of:
1. the guidelines and other deviations specified from the MSC?
2. assignment information including date of shop performed, enough details on the client / project, fee, reimbursement expenses, etc.?
3. receipts relevant to this assignment, even non-reimbursable, but tax-deductible expenses?
4. a copy of the report you submitted to the MSC?
5. all relevant correspondence that can affect you in any ways (bonus, guideline clarifications, etc.)?
6. a copy of payment (whether PayPal, deposit to my bank account via direct deposit or check, etc.)?
If I can answer all 6 questions (typically the first 5 will be what you can answer first for obvious reasons), then I can mark that assignment as 'complete' in my assignment tracker.
Very infrequently shopping the Greater Denver Area, Colorado Springs and in-between in Colorado these days.