i have added custom filed but i am unable to generate custom filed report how can it will be resolved
Please provide much more details, such as Manager version, Edition, OS, Screenshots, steps you took, guide(s) you consulted. Only in such way forum members can provide you with help.
Because you are asking about custom reports, forum rules require that you post screen shots of the definition of your best attempt and the resulting report, explaining how the report does not meet your expectations.
Also, are you aware of the Sales Invoice Totals by Custom Field report in the Reports tab?