I need to find an English song which can be played by piano and flute also it must be easy to sing. Hmu if you know a good one.
Easy to play, easy to sing, you may also add the flute tune to this song without any effort if you know a few notes of course...
You may also pick any of Birdy's songs if you want - they all are pretty simple by design.
Both are quite simple to sing, and piano sheet music can be found online for a few dollars.
It even had a piano+voice arrangement: https://www.youtube.com/watch?v=8wvvcRg-DLk
I'd say it's fairly easy: Laura Pausini is not a native, so the lyrics are quite simple.
Fernando, by ABBA? It's long. But, if you only sing the first verse, it should be easy. Lyrics aren't hard to sing. The flute and piano play different parts. You can leave out the guitar part. It's not necessary. A piano and flute can do it well.
If you only want an easy song to PLAY on the piano and flute (not sing lyrics) I suggest an old classic "GREENSLEEVES". https://www.youtube.com/watch?v=oDoHIVkWXnQ