As with any other building, religious buildings need signs. These can have a wide variety of functions from showing that it is a place of worship, opening hours, events available and hiring ability of the building itself. Whatever the function, the signs need to be clear and concise.
When it comes to the exterior of the building, it is important to have a welcome sign displaying the name of the church, mosque or synagogue. On that note, whilst in many places the design of the building will ddemonstrate the religion being practices within, it is not always so obvious. Therefore, it can be prudent to place a symbol specific to that religion on the sign as well, such as a cross for Christians and a Star of David for Jews.
Other exterior religious signs might be to show current functions and events, or simply a proclamation of the main message of that religion.
Once inside the building, if it is open to the public for visiting, then it is important to clearly display rules within the site. These can include things such as covering of heads, taking off shoes, no photography, speaking quietly and more. Other signs might simply be exit signs and those for toilets.