Dear friends
the credit notes shows a Custom Title as " TAX Invoice" in Arabic “فاتورة ضريبة” even If I converted from Arabic to English language it the same as shown in photos!
I do not think that Manager translates Custom Titles when you change language.
Only the fixed text in the system is translated.
Either combine the english and arabic title into the one Custom field or use a custom theme and put the code into it to translate the title
if you see the Edit screen the option of custom title does not exist
so I did not add custom title to Credit Note
If you go to
Setting → taxcodes
For any if your taxcodes Have you set “custom credit note title” ?
See this note in the guide Change a form title | Manager
and this one Create and use tax codes | Manager has some information on Custom Titles
thanks for your replies
I chicked the Tax Codes there was custom titles and removed 3|690x314
my coleage edited them recently
every thing good now 
