Pope was crowned The Voice's third season winner on Tuesday (December 18), making her the second Team Blake member to become champion.
Speaking to People, Shelton said that now is the time for the 23-year-old singer to explore who she wants to become as an artist.
"She's got a lot of options. She's adored by rock fans, pop fans, country fans. She connects with a lyric the way few people can," he said, adding: "The door is wide open!"
Pope also commented on future, explaining that she wants to blend several of her favorite genres into a new kind of pop music.
"I would love to do the pop/rock thing, but I know that I gained some amazing country fans and I know how hard it is to get into that world," she explained.
"I'd love to add a country music element to it a bit. I used to cover country music when I was a kid and it's stylistically part of my voice somehow."
Shelton found much success in The Voice's third season, with the runner-up to Pope being her fellow Team Blake member Terry McDermott.
The Voice's season finale also featured performances from Rihanna, Kelly Clarkson, The Killers and Bruno Mars.
NBC premieres the reality competition's fourth season in March 2013.
> The Voice: Top 3 perform in grand finale
Watch the crowning of Cassadee Pope as The Voice's winner below: