What is the difference between вводить and входить?
I can't find a (significant) difference in my dictionary(ies).

When would you use one and when the other?
@Natasha - Yeah, I guess context is missing in my question. I'm referring to the meaning or "to enter".

For example, context-reverso has these sentences:
Можно также вводить пробелы и другой фиксированный текст.
Нельзя входить к девушке в комнату без её разрешения.
In this case, context-reverso hasn't helped me at all with my question. They "register" as examples for me, not explanations regarding correctness, frequency of use or anything else. They are merely presented as "correct".

I was and am still confused. Could the other verb be used here without changing the meaning? Which would be more "normal"?

Question

What is the difference between вводить and входить?
I can't find a (significant) difference in my dictionary(ies).

When would you use one and when the other?
@Natasha - Yeah, I guess context is missing in my question. I'm referring to the meaning or "to enter".

For example, context-reverso has these sentences:
Можно также вводить пробелы и другой фиксированный текст.
Нельзя входить к девушке в комнату без её разрешения.
In this case, context-reverso hasn't helped me at all with my question. They "register" as examples for me, not explanations regarding correctness, frequency of use or anything else. They are merely presented as "correct".

I was and am still confused. Could the other verb be used here without changing the meaning? Which would be more "normal"?

Answer

входить is a intransitive verb and means "to go in" or "come in". Eg. входить в комнату

вводить is a transitive verb and has different meanings: to bring in, to put in, to insert etc. Being a transitive verb, it requires a direct object that you are acting upon.

Answer

context.reverso.net/перевод/русский-английский/вводить

context.reverso.net/перевод/русский-английский/входить

Вводят что-то. 
Входят сами.

Answer

1.1. In the abstract sense of joining входить competes with

вступить/вступать 'in-step'.

To enter a war, a club or ranks. Вступить is more common, but there's a difference:

"In-step" is for _intentional_ act of joining. Often with a formal procedure. 
"In-walk" is a statement of fact: it is in now. Intentionally or not.

In some contexts only one makes sense:

Вступительные экзамены.
процедура вступления в...
Встyпил в должность.

входит в число самых ... Is among the most... (yes, I want to be in that number, when the saint go marching in!)
вошел в число ...
вошел в список.... entered the list of...
 
With "club" or "rank" both are possible but the shade changes.

1.2. When you use it literally, "войти/входить" "to come in" is more common. 
It is one of two usual words for "come in", the other being "зайти".

вступить в комнату is also possible, even торжественно вступить в комнату.
But this simply means "to step in [the room]":)

Answer

to enter a room is 
входить 'in-walk', 'in-go'

to enter in the sense of "put in" or "input" is
вводить 'in-lead'.

Answer

Okay..Active/passive...transitive/intransitive... 
That I can deal with.
Thanks.