There are many ways, but they fall into seven categories:

(1) attached to a wall or door by countersunk screws or bolts through the face, threaded studs embedded in the back of the sign or plaque, Z-clips (thin aluminum French cleats), glue, or hanging from a screw or nail  

(2) hard-mounted to a single wrought iron or wood post using a special custom steel bracket (single-faced and double-faced signs);

(3) hard-mounted between two wood posts (single or double-faced signs) using steel flat bar side brackets ;

(4) hanging from two chains or rigid steel struts connected to a transverse wood beam mounted  between two iron or wood posts (single or double-faced signs):

(5) hanging from two chains on an projecting iron or wood bracket mounted on a wall (i.e., called a blade sign) or a single wood post (usually double-faced signs)

(6 ) mounted on a concrete, stone, brick or wood base fixed to ground (single or double-faced signs), usually  referred to as monument signs

( 7) mounted on a flat or sloped roof with a wood frame attached to the roof.

 Smaller signs (6 inches to 2 ft wide) use methods (1) , (2) , (5) and (6); larger signs (3 ft to 10 ft wide) can use methods (1), (3), (4), (5), (6) and (7). The largest signs (6 to 20 ft in width) use methods (1), (3), (4), (6) and (7). We make and sell as catalog items (1) through (5). For more details request our detailed guide for installing wall and post signs.