How do I state the amount of money I have in a legal paper? And what word should I use instead of 'money'?? Like: I have 10000 $ which equals 2000 £.
Very liquid assets such as physical cash and/or bank accounts you can withdraw and have immediately should be described as cash: "I have $50,000 in cash." E.g. $1000 in my mattress and $49,000 in a bank debit account.
Things like bonds, etc. should be described as such, "I have $50,000 in cash and $20,000 in an IRA and $30,000 savings bonds." A good non-financial term for things other than cash is savings - so here you could say "I have $50,000 in cash and $50,000 in savings."
BUT, since this is a legal paper, you really should consult with a legal expert or at least discuss with the person who wants you to fill out the form. Legal documents are in their own world with language and saying the wrong thing in the wrong way can have serious consequences.