Yes. Your input name and message will be shown on screen as per normal depending
on the streamer's donation settings.
As streamers may set up their StreamElements or StreamLabs in USD, it would be
more accurate to have the donations based on the respective currency. The donation itself would
still be sent in SGD and recieved by the streamer in SGD.
The USD-SGD exchange rate is fixed at 1.362245 and is adjusted annually. This
value is the daily average exchange rate
between 1 Jan 2019 - 1 Jan 2022 (ofx.com). It is a simple gauge to
convert USD to SGD.