The bar horizontal line is to indicate a long vowel in Japanese
for a foreign origin word.
"－" is a mark.
We basically don't use it in Hiragana.
(But we can see "－" in Hiragana,for example on signboards and advertisements.)
When we write words which we call Gairaigo, coming from overseas,
we use "－" in Katakana.
For example, when we want to write an English word “cheese” in Hiragana,
it will be ちず as we don’t use the mark “－”.
ちず doesn’t mean “cheese” but a map.
Then,we have to write “ちいず” in Hiragana as it sounds.
But “ちいず” is Gairaigo,so we write “チーズ” in Katakana.
ちいず → チーズ
らあめん → ラーメン
びいる → ビール
すうぷ → スープ
げえむ → ゲーム
ごおる → ゴール