This is the 4780th most frequent Portuguese word.
estender
To extend or to stretch out.
This usage of 'estender' refers to 'to extend' as in lengthening or prolonging a deadline or timeframe.
Tentarei estender o prazo do pagamento com o banco.
I will try to extend the payment deadline with the bank.
In this sentence, 'estender' means 'to spread' or 'to unfold' as in laying an item down to use (like a towel).
Eu vou estender a toalha na areia.
I will spread the towel on the sand.
Here, 'estender' means 'to extend' as in physically offering assistance or metaphorically showing a gesture of help.