Citizens of many countries are exempt from obtaining a visa in advance. Every tourist must check, before leaving for a visit to Israel, whether a visa is required from the local Israeli representative office.
The Ministry of Foreign Affairs website contains a list indicating the country and the requirement for its approval: http://mfa.gov.il/MFA/ConsularServices/Documents/VisaRequirements-Tourists.pdf
Every visitor must present a passport that can be scanned by an international computer system. If a visitor arrives with a pass-through card only, he/she must provide a visa from the Israeli embassy in his/her country of residence. More information is available on the Ministry of Foreign Affairs website: WWW.MFA.GOV.IL
Visitors with a tourist visa may stay in Israel for up to three months from the date of arrival, and in accordance with the conditions of the visa granted to them at the border crossing. Visitors wishing to work in Israel must apply for the appropriate approvals from the Administration of Border Crossings, Population and Immigration.