Q: How to see sent n trash mails etc on pale I phone 5

I do not understand what you mean by "sent n trash mails"

Did you delete the send emails and now want them back?

Maybe (from manual):

Recover a deleted message. Go to the account’s Trash mailbox, open the message, then tap and move the message. Or, if you just deleted it, shake iPod touch to undo. To see deleted messages across all your accounts, add the Trash mailbox. To add it, tap Edit in the mailboxes list and select it from the list.

Stash your trash. You can set how long deleted messages stay in the Trash mailbox. Go to Settings > Mail, Contacts, Calendars > account name > Account > Advanced.

Go to mailboxes and tap on Sent

What type of account is it? IMAP or POP3?

Who is the provider?

Did you send them from the phone?

Post a screen shot showing what mailboxes you have available.