Shirt embroidery is the most common garment ordered for convention and event planners, and is even more popular than hats or bags. The types of shirts, whether they be t shirts, polo shirts, t shirts or work shirts is just as varied as to the location and size of the embroidered logo being sewn upon it.
Then there is the consideration of fabric. A great online embroiderer such as True to Size Apparel will go the extra mile and custom modify their embroidery file so that you get a better result when embroidering polyester or cotton. Of course, your logo's digitized embroidery file is modified again when the clothing is a hat. Buyers of custom logo embroidery should confirm that such consideration as to modify their embroidery file has been given, so that your message or brand is best represented when worn.
The advantage of polyester fabric is that perspiration does not swell the fiber and therefore not block your body sweat and heat. The lack of insulation allows the person wearing the shirt to be cooler, more comfortable and to hold body odor. Polyester is smoother to the touch ( a soft hand ) and costs almost as much as cotton, as poly fabric cost has dropped a great deal recently.
When using polyester, do note that your embroidery is going to pucker somewhat more than when using cotton fabric. You can minimize pucker and save embroidery cost when your logo is more of an outline and does not use dense or concentrated areas of thread. I am a big fan of tearaway versus cutaway backing for shirt embroidery so that the person wearing the shirt has a more comfortable garment.
When buying button down dress shirts or work shirts, the fabric is almost always a cotton twill, 100% cotton or blend. You have a greater latitude with a higher stitch count custom logo and you can place that logo in many areas and are not confined to the left chest. My favorite locations are the collar front and back, followed by the shoulder top & sleeve area. Anywhere near eye level that is easily picked up by a potential customer works. Look at all of the logos on the golfing champions! If in doubt, follow the money when making decisions about your money, look at how people & companies with money spend their own cash.
Give yourself some time before your purchase and do two things. Buy more than one style and in varied sizes before the big order. Let the decision makers try on a shirt to see if they are comfortable enough to wear it long after the event is over, assuming the shirt is not a uniform garment. There is no such thing as true to size, so have someone who always wears a medium size, for example, put on the intended style's medium to see if for your purposes the size runs big or small. Get a shirt sewn as desired before ordering a custom embroidery order that cannot be exchanged or returned.
Have a great time & make a lot of new friends and money.