Many of us use Butternut HF6V antenna on HF bands. It’s very good antenna for small places and allows to operate on 80m to 10m bands however 60m band isn’t not included.
With FT8 mode running around the globe 60m band become very popular and propagation is very unique on that band. The power on 60m band is limited so with vertical antenna power can be only 50 watts which is enough for digital modes.
To add 60m band to HF6V antenna you just need a simple wire jumper. I’ve seen some other modifications with relay but I personally prefer a simplicity. Jumper used on 80m coil and short most of turns. As you can see on photo in my case the jumper on 5.5 turn of 80m band coil. I would suggest to verify with SWR meter or antenna analyzer for low SWR. Since my antenna on 80m band tuned in CW frequency range the resonance on 5357MHz occurs with putting jumper on 5.5 turn.