Poker
A topic on the cited 7bet-app.com page; PokerStars Texas Hold'em is the rule example.
7bet · Game topics and rules

In Texas Hold'em, the hand that matters at showdown is the best five-card combination available from two private cards and five shared cards. Counting all seven as one hand gives the wrong result.
This page explains game formats and rules; it is not a playable lobby. Check the relevant service for current game availability and the exact version in use.
A topic on the cited 7bet-app.com page; PokerStars Texas Hold'em is the rule example.
Sport topics whose results are scores over time, not poker hands.
A broad topic label, not proof of a Texas Hold'em table.
PokerStars describes two hole cards per player and five possible community cards. Three arrive on the flop, one on the turn and one on the river. At showdown, each remaining player selects the best five of the seven available cards.
There is no requirement in Texas Hold'em to use both hole cards. Sometimes one private card improves the board; sometimes the board's five cards already make a player's best hand.
Suppose the hole cards are A♠ and 7♦, and the final board is A♥, 7♣, K♠, 2♦, 9♣. The best five are A♠, A♥, 7♦, 7♣ and K♠: two pair, aces and sevens, with a king as the fifth card. The 2 and 9 are not part of that five-card hand.
An opponent with A♦ and Q♦ on the same board has one pair of aces, not two pair, because only one seven is on the shared board and neither private card supplies another. Under traditional hand rankings, two pair beats one pair. This is a hand-comparison example, not a claim about a current table.
Before the river, fewer than five community cards are visible, so a possible improvement may fail to arrive. A four-card flush draw is not yet a five-card flush. PokerStars ranks a completed flush above a straight but below a full house in traditional high-hand Texas Hold'em.
The poker topic on the cited page does not fix a table variant, betting limit or availability. Read the named table's rules before importing this Texas Hold'em example into another poker form.
No. The best five may use zero, one or both of the two private cards.
Two pair, aces and sevens, with a king as the fifth card.
No. A flush requires five cards of one suit.