Understanding The Arguments for SMTPlib - sendmail

[buran]

But when i open the brackets for this command a dialogue menu opens which shows the arguments and each argument as a : not a =, so would interpret all : as equals?

It's not clear what you mean by "a dialogue menu opens"? Do you mean that you get some inetlisense hint as to what the arguments are expected?
Maybe look at basics as to how you pass [keyword] arguments to functions.