At times, I have heard: “I’ve been working here from 2015.”
Actually it should be: “I’ve been working here since 2015.”
Or one can say: “I’ve been working here for two years.”
Here is how since and for are used:
since + point in time (since 1906)
for + period of time (for 10 years)
We do use from with time expressions, but in a different sense. Here are some examples:
The conference starts from tomorrow.
The shop is open from 9:00 am to 5:00 pm.
And yes, by now you know why the ad is correct: Trusted since 1906.
In fact, from now on, you know the difference between since and for.