Refers to a single step or stride in walking. Often used in set phrases like 歩を進める (take a step forward) or 歩を緩める (slow one's pace).
He didn't move a single step.
counter for steps
Used to count steps or strides. Commonly appears with numbers, e.g., 一歩 (one step), 二歩 (two steps).
I aim to walk 10,000 steps every day.
I slowed my pace because I was getting tired.
I quickened my pace and headed to the station.
Just three more steps to the goal.
He suddenly stopped in his tracks and turned around.
Please move forward three steps.
It's dangerous, so please step back two steps.
足 refers to the foot or leg itself, while 歩 refers to a single step or stride taken with the feet.
歩く is the verb 'to walk', whereas 歩 is the noun (or counter) for a single step, so they cannot be swapped grammatically despite sharing the kanji.
歩 read as ほ means a step or pace in ordinary Japanese, whereas 歩 read as ふ is the shogi term for a pawn; same kanji, different reading and meaning.
Standard kanji spelling for both the noun and counter senses.
The kanji 歩 depicts a foot and originally meant 'to walk'. The reading ほ is the Sino-Japanese on'yomi, used in many compounds related to walking or steps.
basics; rudiments; first steps
number of steps; step count
pace; step; cadence
striding; swaggering; strutting · lording it over others; throwing one's weight around; acting as if one owns the place
racewalking; race walking
step length; stride; pace
walking alone; walking without assistance · self-reliance; independence · unique; unparalleled; peerless
snail's pace; slow progress
sentry; sentinel
steady progress; rapid advance
walk; stroll; promenade
one step; a step · step; stage; level · a little; a bit; slightly
how many steps
good walker; strong walker
half step; half a step
national fate; prospects of a country
foothold; footing; standing
long strides
walk (horse gait)
walking slowly; slow walk
several steps; a few steps