Before Queen Elisabeth was the queen the text was God Save the King and offcourse when Charles becomes the king, it will again be God Save the King.
For some Commenwealth contries 'God Save the Queen' is the Royal Anthem (not the National Anthem)
Here's the lyrics:
God save our gracious Queen!
Long live our noble Queen!
God save the Queen!
Send her victorious,
Happy and glorious,
Long to reign over us:
God save The Queen!
O Lord our God arise,
Scatter her enemies,
And make them fall:
Confound their politics,
Frustrate their knavish tricks,
On Thee our hopes we fix:
God save us all.
Thy choicest gifts in store,
On her be pleased to pour;
Long may she reign:
May she defend our laws,
And ever give us cause,
To sing with heart and voice,
God save the Queen!