This is the 2034th most frequent Russian word.
telegram
A message sent over a telegraph network, typically brief and transmitted electronically or by wire.
Here, 'телеграмма' refers to a traditional form of communication, the telegram.
Я получил важную телеграмму вчера вечером.
I received an important telegram last night.
In this context, 'Телеграмм' refers to the messaging application Telegram.
Я подписался на новый канал в Телеграме.
I subscribed to a new channel on Telegram.
The word 'телеграммы' in this sentence refers to the act of sending messages via a telegram service, now considered an old-fashioned practice.