What this generator does and does not do
It does the arithmetic and gives you a document you can send. Quantity times unit price per line, subtotal, VAT at the rate you set, total. The standard VAT rate in Israel is 18 percent, and the field is editable because zero-rated and exempt cases exist.
What it cannot do is make the result a legal tax invoice. In Israel a tax invoice has to carry a number from an unbroken sequence, it has to be kept in a form that cannot be edited after issue, and above a certain amount it needs an allocation number from the Tax Authority before it is valid for the customer to deduct input VAT. A page that generates a PDF has no way to guarantee any of that. Details are in the invoice checklist and the VAT guide.
Use this for a quote, a proforma, or a customer who just needs the numbers on paper. When you need a real tax invoice with sequential numbering, a frozen copy of the issued document and allocation numbers requested automatically, move to Slate.