This is mostly because boric acid is commonly believed to have different acidity mechanism. While common acids generally dissociates

$\ce{HNO3 <=> H+ + NO3-}$

boric acid is commonly believed to associate with water

$\ce{H2O + B(OH)3 <=> H+ + [B(OH)4]-}$

this type of acidity is rather common for metal hydroxides, hence the way of writing.

This is mostly because boric acid is commonly believed to have different acidity mechanism. While common acids generally dissociates

$\ce{HNO3 <=> H+ + NO3-}$

boric acid is commonly believed to associate with water

$\ce{H2O + B(OH)3 <=> H+ + [B(OH)4]-}$

this type of acidity is rather common for metal hydroxides, hence the way of writing.

For that matter, not every hydrogen should be written at the beginning of a formula of an acid, but only actually acidic ones. So, $\ce{H2SO4}$, but $\ce{HPH2O2}$

This is mostly because boric acid is commonly believed to have different acidity mechanism. While common acids generally dissociates

$\ce{HNO3 = H+ + NO3-}$

boric acid is commonly believed to associate with water

$\ce{H2O + B(OH)3= H+ + [B(OH)4]-}$

this type of acidity is rather common for metal hydroxides, hence the way of writing.

This is mostly because boric acid is commonly believed to have different acidity mechanism. While common acids generally dissociates

$\ce{HNO3 <=> H+ + NO3-}$

boric acid is commonly believed to associate with water

$\ce{H2O + B(OH)3 <=> H+ + [B(OH)4]-}$

this type of acidity is rather common for metal hydroxides, hence the way of writing.