It is present tense.
The past tense of "work" would be "worked".
I, you, we, they work. She, he, it works.
Worked is the past tense of work. Present tense forms of work are: work / works / working
Present tense: work/works/working Past tense: worked. Future tense: will work.
The past tense of "work" would be "worked".
The past tense is worked. The present tense is work/works/working.
The past tense for "This work is easy" is "This work was easy."
The present tense of work is work (I work, you work, he works, she works, it works, we work they work). The present continuous - am/is/are working; the present perfect - have/has worked; the present perfect continuous - have/has been working.
Present tense.
What is the future tense of this sentence, "I work very hard."
It is work/works.
Inappropriate changes would be called "problems with tense." Appropriate use of tense in a literary work involves maintaining the tense throughout the work. If you are writing in the present...verbs are in present tense; if writing in past tense, verbs will be in past tense, etc for future tense.