Thank you very much for your congratulations.
If you humbly do something you are going to humbly receive, to humbly accept, or eat or drink it. Basically you're humbly doing a lot of things. And you can use this word for all of them!
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn this reading yet, so here's a mnemonic to help you:
You technically already know this reading! You know how people say いただきます? Well that's the same as this! You're humbly receiving your meal. So to humbly receive is いただく!