Badges are commonly found on Boy Scout or Girl Scout uniforms, military uniforms, work shirts, company-affiliated totes and other items, and anything else you can imagine. Recently, many adhesive products have become available with which you can attach badges without sewing. However, you will find it very difficult to remove badges that were adhered with these products if removal becomes necessary. Hand-sewing is really not much more difficult, and is the safer choice for attaching badges to various items under most circumstances.
Set the badges in place. Use straight pins to temporarily attach them and keep them still.
Choose a thread colour that closely matches the thread used around the hem of your badge. Thread a standard sewing needle with a double-length of the thread.
Place the tip of the tip of the needle close to the edge of the badge from beneath. Push up through both the base fabric and the badge and pull the thread through. Catch approximately 1/4 inch of thread with your fingers and hold it.
Turn the needle away from you and push the tip into the base fabric very near the end of the badge; pull the thread through to create a whipstitch over the edge of the badge. Use your thumb to hold down the tail of thread that you caught and begin another whipstitch from the bottom. Make sure that when the loop of thread tightens, it catches the loose thread under your thumb to hold it tight.
Continue to whipstitch around the badge; make the first three to four stitches over the tail of thread to secure it. Finish the sewing with the needle hanging from the backside of the fabric. Snip the remaining thread away with scissors, leaving approximately 1/4 inch; press the thread against the fabric back with a warm iron or tie the thread in a double knot to hold.