What should I do if I forget my username and password?

First, Click on the “login” option at the top of the page, on the left. 
After that click on the “forgot the password” link .
Now, you should enter your email address. You will receive confirmed email for changing password.
Then you will receive an email authorizing you to change your password.

Can you submit your manuscript to the different journals?

No. This is unethical in publishing. If it happens, your manuscript will not be published;
And if it is published before, it will be invalid. Then, your name will be blacklisted and no other manuscripts will be accepted from you.

Is there any charge for authors to publish their manuscripts in this journal?

No, the Journal of Iranian journal of Pulses Research does not receive any money from authors.