I have activated the safari option and the keyring option and dont save any password
In my ipad 2 with 6.1 works perfect, but my iPad Air with 7.0.3 save nothing
Most likely culprit here is Safari. Open your Safari web page, then click the page icon on the right upper corner. This will minimize the page and give you the option of adding another page etc. There you will also find a "Private" tab, if it is white you have selected private browsing and Safari will not remember any passwords. Click it to deselect, then verify your settings allow your device to remember passwords.
One indication you are in private browsing is that Safari will not have anything on the history pages.