In a generalized fashion, the job of a preamp is to amplify the signal at the antenna in order for said signal to have sufficient power to traverse a long feed line to your distribution point.
The job of an amplifier is to amplify the signal prior to splitters and long household runs of cable.
ANT–>PreAmp/ LTE Filter (If needed)---->Cable run to Amplifier(if Needed)–>Splitters–>Tuners
PreAmplifiers are intended to be as close to the actual antenna as possible- usually directly on the antenna directly after the balun.
Distribution Amplifiers (What you normally see listed as just an amplifier) are intended to be used at the drop (Where the antenna line actually enters the house) before any splitters to overcome the signal losses due to splitters and/or long cable runs inside the home.
The biggest difference between the 2 is shown in a metric that you need a direct connection to (many?) televisions RF in: Signal QUALITY. (Tablo shows you signal STRENGTH.) Signal quality has to do with the ratio of SIGNAL to NOISE, which all amplifiers adversely effect. (A preamp will typically have better SNR numbers partially due to a better physical location closer to the antenna, but YMMV depending on brand/ model/ details)